Semiconductor products used in, for instance, LSI (large scale integrated circuit), a solar cell and a liquid crystal plasma display are formed in a film-forming device wherein thin films are formed on a substrate using a film-forming material according to a variety of film-forming methods such as vapor deposition, sputtering, CVD and other film-forming techniques.
The film-forming material is also adhered to the surface of components of film-forming device such as a deposition-inhibiting plate, for instance, a mask for substrates and a frame for supporting wafers, during the thin film-forming process.
When such film-forming treatments are repeated while exchanging substrates in the same film-forming device, the foregoing film-forming material adhered to such components increases its thickness because of the accumulation thereof and the deposited film may be broken, peeled off and may fall off from the components at a certain point of time. This becomes a cause of dust-generation and the dust may be adhered to the substrate on which a film is just in course of formation and may impair the desired characteristic properties of the resulting film. This would in turn reduce the yield of the semiconductor products thus produced.
Under such circumstances, there has been adopted, for instance, a washing or cleaning method in which components having films adhered thereto are immersed in a cleaning solution as a means for removing the foregoing adhered film.
The foregoing cleaning requires the interruption of the film-forming device before the adhered film is broken, peeled off and/or falls off, but it is quite difficult to correctly ascertain the instance when the adhered film is broken, peeled off and/or falls off. On the other hand, if such components are frequently washed without any confirmation of the instance when the Adhered film is broken, peeled off and/or falls off, a problem arises such that the operating efficiency of the film-forming device is considerably reduced.
There have conventionally been proposed components having a surface structure as shown in the attached FIG. 3, which would make any breakage, peeling off and/or falling off of an adhered film difficult, even when the adhered film is thick and which is disclosed in Japanese Un-Examined Patent Publication Hei 8-277460. The use of such a component having the foregoing structure would permit the solution of the foregoing problem of the breakage, peeling off and/or falling off of the adhered film even when the film-forming material is deposited on the component to a certain thickness and the elimination of such frequent cleaning of the components and therefore, the operational efficiency of the film-forming device has thus been substantially improved.
FIG. 3(a) attached hereto shows a basic material 31 constituting a component of a film-forming device, (hereunder simply referred to as “component”), whose surface is roughened according to a shot blasting technique in which the surface of the basic material is bombarded with steel balls having a small diameter or a glass bead-blasting technique in which glass beads are impacted against the surface thereof. The unevenness of the surface would permit an increase in the surface area of the basic material 31, the adhesive force of the film d adhered to the component increases and this accordingly permit the prevention of any breakage, peeling off and/or falling off of the adhered film d.
FIG. 3(b) attached hereto shows a basic material 32 constituting a component whose surface is roughened according to a mechanical processing method such as cutting and embossing techniques. In this case, the surface of the basic material 32 undergoes deformation in response to the stress applied onto the adhered film d and liable to cause peeling off of the film to thus relieve the stress. Therefore, any breakage, peeling off and/or falling off of the adhered film d can be prevented.
FIG. 3(c) attached hereto shows a basic material 33, which is first subjected to blasting as has been described above to thus give roughened surface and then coated with a tender metal to form a layer 34 on the surface of the basic material 33. Thus, the stress, which acts on the film d adhered to the component to thus cause breakage, peeling off and/or falling off thereof, can be relaxed because of the presence of such a tender metal layer 34 and accordingly, the latter permits the prevention of any breakage, peeling off and/or falling off of the film d.
When repeating such a film-forming treatment over considerable times, the film adhered to the component is, after all, broken, peeled off and/or falls off from the component, even when using the conventional component having the foregoing structure and accordingly, the component should be cleaned in order to reuse or recycle the same.
However, the component has such a structure, which makes any breakage or peeling off and/or falling off of the film adhered thereto, difficult. For this reason, it takes a long period of cleaning time to completely remove the film adhered to the component through the dissolution thereof using a cleaning solution and this in turn results in the substantial reduction of the operational efficiency of the film-forming device.
Moreover, the component per se is also immersed in the cleaning solution over a long period of time since a long period of time is required for the removal of the film adhered to the component and the cleaning solution may thus deteriorate the component.
In case where a long period of time is required for the cleaning, the component may be replaced with a fresh one. In case of, for instance, a mask for substrates whose size has gradually been increased in response to the need for a large-sized liquid crystal image plane, however, the frequent exchange thereof would instead result in an increase in the cost and labor for the production of thin films. Therefore, there has strongly been desired for the development of a technique, which permits the removal of such a film adhered to the component through cleaning and which makes it possible to reuse the component.
Accordingly, it is an object of the present invention to solve the foregoing problems and more specifically to provide a component for a film-forming device, whose surface structure makes any breakage, peeling off and/or falling off of a film adhered to the component difficult, while the structure permits easy removal of such an adhered film within a short period of time when cleaning the component.